2-aminoethanesulfonic acid zinc complex compound

ABSTRACT

PCT No. PCT/JP93/00813 Sec. 371 Date Dec. 15, 1994 Sec. 102(e) Date Dec. 15, 1994 PCT Filed Jun. 14, 1993 PCT Pub. No. WO93/25558 PCT Pub. Date Dec. 23, 1993.The present invention covers 2-aminoethanesulfonic acid zinc complex compound as represented by the formula [I]:   &lt;IMAGE&gt;   as well as a process for producing the same, and an anti-hepatitis agent, liver function improving agent and anti-ulcer agent. As compared with 2-aminoethanesulfonic acid, glutathione and glycyrrhizin, the compound (I) of the present invention exhibits improved anti-hepatitis activity, and also strengthens detoxicating activity toward various compounds to thereby develop liver function improving activity, while the said compound shows excellent anti-ulcer activity but greatly lowered toxicity.

CROSS REFERENCE TO RELATED APPLICATION

This aplication is a request for U.S. Examination under 35 U.S.C. §371of International application No. PCT/JP93/00813 filed on Jun. 14, 1993.

1. Technical Field

The present invention relates to a novel 2-aminoethanesulfonic acid zinccomplex compound, to a process for producing the same and to ananti-hepatitis agent, liver function improving agent and anti-ulceragent which individually contain the same as an active ingredient.

2. Background Art

2-Aminoethanesulfonic acid (taurine) is already known to possess liverfunction protecting activity, but with its weak activity, cannot beexpected to find application as an excellent anti-hepatitis agent andliver function improving agent.

The present inventors, with a specific view to preparing improvedpharmaceuticals based on 2-aminoethanesulfonic acid derivatives, haveconducted intensive testing for their pharmacological activities. In thecourse of this, it was discovered that the reaction of2-aminoethanesulfonic acid with an alkali agent and zinc compound canyield [bis(2-aminoethanesulfonic acid).bis(alkali2-aminoethanesulfonate)]zinc as represented by the following formula(Japanese Patent Application No. Hei 4-24642 (1992): ##STR2## (wherein Mis an alkali metal).

The compounds of the formula (A), which possess greater antihepatitisactivity, liver function improving activity and antiulcer activity than2-aminoethanesulfonic acid, still show relatively reduced zinc contentsas low as 10.76 and 10.21% in the cases of M being sodium and potassium,respectively. In the light of the above, the inventors carried outfurther research and synthesized bis(2-aminoethanesulfonic acid)zincwith a zinc content of 20.85%. Pharmacological tests indicate that thezinc complex compound, when compared with the compounds of the formula(A), exhibits more markedly potent anti-ulcer activity as well ascomparable anti-hepatitis and liver function improving activities, andthe finding was followed by additional research, leading to thecompletion of the present invention.

DISCLOSURE OF THE INVENTION

The present invention relates to a 2-aminoethanesulfonic acid zinccomplex compound represented by formula [I]: ##STR3## and to a processfor producing the same as well as to an antihepatitis agent, liverfunction improving agent and anti-ulcer agent.

The compound of formula (I) can be produced by reacting a zinc compound(0.5 mole) with an alkali metal 2-aminoethanesulfonate (1 mole).

The alkali metal 2-aminoethanesulfonate can be prepared by reacting2-aminoethanesulfonic acid (1 mole) with an alkali agent (1 mole). Theresultant alkali metal salt may be reacted with the zinc compound afterbeing isolated, but can also be reacted with the zinc compound as suchwithout being isolated.

As the alkali agent, there can desirably be used alkali metalalcoholates, such as sodium methylate, sodium ethylate, potassiummethylate, potassium ethylate or potassium t-butoxide.

Referring to the zinc compound, zinc bromide and zinc iodide arepreferred, but other zinc compounds may be utilized.

The reaction of the zinc compound with the alkali metal2-aminoethanesulfonate is normally conducted in a suitable solvent, suchas methanol and ethanol, at room temperature or under warming forseveral hours, and after conclusion of the reaction, the reactionproduct can be purified by conventional means.

The compound of formula (I) possesses improved anti-hepatitis, liverfunction improving and anti-ulcer activities, and shows reducedtoxicity, thus being useful as an anti-hepatitis, liver functionimproving and anti-ulcer agent. The compound, either per se or afterbeing mixed with pharmacologically acceptable, appropriate excipients,carriers, diluents, etc., can be administered orally or parenterally invarious dosage forms, such as tablets, capsules, powders, syrups andointments. The compound is administered to patients at varied dosesdepending upon their symptoms, age, body weight, route of administrationand the like, and is normally given to adult patients orally at a singledose of 50 to 200 mg, twice to three times a day.

Described below are Examples and Test Examples to illustrate the presentinvention in more detail.

EXAMPLE

A 11.3 g quantity of zinc bromide was dissolved in 100 ml of driedmethanol, and a solution of 12.5 g (0.1 mole) of 2-aminoethanesulfonicacid and 19.3 ml (0.1 mole) of 28% sodium methylate methanol solution in220 ml of dried methanol was added dropwise to the solution at 60° to70° C. under stirring, followed by stirring at the same temperature for2 hours. After the solution was cooled, the precipitate thatcrystallized out was recovered by filtration and washed with driedmethanol to give 22.6 g (yield of 92.6%) of [bis(2-aminoethanesulfonicacid)]zinc in the form of a colorless powder. m.p. 330° C. (decomp.).

Elemental analysis (%): C₄ H₁₂ N₂ O₆ S₂ Zn Calcd.: C: 15.31, H: 3.86, N:8.93, Zn: 20.85 Found: C: 15.20, H: 3.77, N: 8.64, Zn: 20.60 IR (KBr,cm⁻¹): 3298, 3263, 3183, 2985, 1622, 1508, 1464, 1408, 1369, 1309, 1234,1221, 1176, 1150, 1106, 1064, 1047, 994.

Test Examples (Test compounds)

1) Bis(2-aminoethanesulfonic acid)zinc (the compound of the presentinvention, as hereinafter referred to briefly as "TTZ").

2) [Bis(2-aminoethanesulfonic acid).bis(2-aminoethanesulfonate)]zinc(the product of Japanese Patent application No. Hei 4-24642 (1992),hereinafter referred to briefly as "FTZ").

3) 2-Aminoethanesulfonic acid

4) Glutathione

5) Glycyrrhizin

1. Anti-hepatitis test

(1) Hepatopathy in mice

A group of 8 ddy strain male mice (weighing about 30 g) kept fastingfrom the previous day was treated by intraperitoneal injection of 0.5%carbon tetrachloride in olive oil at a dose of 0.6 ml and thereafterallowed free access to food. Three hours after the administration ofcarbon tetrachloride, the test compound suspended in powdered gum arabicwas given to the animals orally at a dose of 200 mg/kg, and bloodsamples were drawn from the mice under anesthesia with ether through theabdominal descending aorta 24 hours after the administration of carbontetrachloride. The collected blood was centrifuged at a rate of 3,000rpm for 15 min, followed by measurement of the activities of aspartatetransaminase (AST) and alanine transaminase (ALT) by means of the Lippiemethod. The results are shown in Table 1.

                  TABLE 1                                                         ______________________________________                                        Test                                                                          compound AST IU, mean ± S.D.                                                                        ALT IU, mean ± S.D.                               ______________________________________                                        Treated  11884.2 ± 2042.1                                                                           12677.9 ± 828.2                                   group                                                                         TTZ       7256.9 ± 1464.7*                                                                           8899.4 ± 927.9*                                  FTZ       7024.7 ± 1113.4*                                                                           8597.1 ± 1450.4*                                 2-Amino- 12885.2 ± 2468.3                                                                           14609.6 ± 1684.5                                  ethane-sul-                                                                   fonic acid                                                                    Glutathione                                                                            11423.3 ± 1960.8                                                                           12030.2 ± 1204.5                                  Glycyrrhizin                                                                           12367.6 ± 1102.1                                                                           13362.1 ± 1753.1                                  ______________________________________                                         Note:                                                                         *Level of significance p < 0.05                                          

TTZ, or the compound of the present invention, exhibited significantsuppressory activity equal to that of FTZ, whereas none of2-aminoethanesulfonic acid, glutathione and glycyrrhizin that were usedas controls at the same dose developed suppressory activity.

(2) Disorder of isolated liver cells

Isolated liver cells of rats were prepared by means of the Segren'scollagenase irrigation method, whereby a liver cell suspension wasprepared to a concentration of 6×108 liver cells/ml. Into 2 ml of thesuspension placed in an Erlenmeyer flask was put a test tube of about0.5 ml capacity containing a 25% carbon tetrachloride solution in oliveoil to saturate the reaction system with carbon tetrachloride vapor, andafter the flask was tightly stoppered, preincubation was carried out at37° C. for 30 min. One ml of a solution of the test compound in Hunk'ssolution was added to the suspension of liver cells, while 1 ml ofHunk's solution was added to a control. After the reaction was allowedto proceed at 37° C. for 30 min, a specifically determined volume of thereaction solution was pipetted out and immediately centrifuged under 500g for 30 seconds, and ALT and AST leached out into the supernatantliquid were determined for activity by the Lippie method. The resultsare shown in Table 2.

                  TABLE 2                                                         ______________________________________                                        Test      Conc. of test                                                                            ALT IU      AST IU                                       compound  soln. (mg/dl)                                                                            mean ± S.D.                                                                            mean ± S.D.                               ______________________________________                                        Non-treated          549.5 ± 33.8                                                                           254.4 ± 12.9                              Treated group        1158.5 ± 136.7                                                                         379.1 ± 39.4                              TTZ       0.1        525.1 ± 26.0*                                                                           44.3 ± 11.1*                                       0.05       649.1 ± 42.4*                                                                          68.2 ± 7.5*                                         0.025      637.2 ± 93.7*                                                                          125.7 ± 48.2*                                       0.0125     944.7 ± 61.7*                                                                          327.9 ± 36.6*                             FTZ       0.1        435.7 ± 25.3*                                                                          33.5 ± 3.5*                                         0.05       389.2 ± 7.3*                                                                            79.4 ± 12.3*                                       0.025      459.0 ± 93.8*                                                                          186.8 ± 35.3*                                       0.0125     414.7 ± 36.2*                                                                          198.2 ± 22.5*                             2-Aminoethane-                                                                          0.1         867.7 ± 158.8*                                                                        318.8 ± 49.5*                             sulfonic acid                                                                           0.05       849.1 ± 60.2*                                                                          296.3 ± 30.5*                                       0.025      869.8 ± 87.6*                                                                          309.8 ± 32.4*                                       0.0125     847.6 ± 60.4*                                                                          338.8 ± 37.1*                             ______________________________________                                         Note:                                                                         *Level of significance p < 0.05                                          

TTZ, or the compound of the present invention, exhibited suppressoryactivity equal to that of FTZ but clearly superior to that of2-aminoethanesulfonic acid alone.

2. Test on liver function improvement

(1) Protective activity against acetaldehyde toxicity:

Rats kept fasting with a supply of drinking water were weighed anddivided into groups in such a manner that the mean body weight wasuniform among the groups, with each group consisting of 10 heads. Therats were given acetaldehyde orally at a dose of 1,200 mg/kg, and thedeath rate within 24 hours was determined, wherein the test drugsubstances were administered orally 30 min before the application ofacetaldehyde, with the vehicle (0.5% aqueous sodiumcarboxymethylcellulose) alone being given to a control group. Theresults are shown in Table 3.

                  TABLE 3                                                         ______________________________________                                                     Dose     No. of dead  Death rate                                 Test drug substance                                                                        (mg/kg)  animals (n/10)                                                                             (%)                                        ______________________________________                                        Vehicle      --       10/10        100                                        TTZ          150      3/10         30                                         "            300      0/10          0                                         FTZ          250      4/10         40                                         "            500      2/10         20                                         2-Aminoethane-                                                                             250      6/10         60                                         sulfonic acid                                                                 2-Aminoethane-                                                                             500      5/10         50                                         sulfonic acid                                                                 ______________________________________                                    

TTZ, or the compound of the present invention, was found to exhibitdistinct protective activity against the lethal toxicity of acetaldehydeat lower doses than FTZ, which activity was shown to be more potent thanthat of 2-aminoethanesulfonic acid.

3. Anti-ulcer test Animal used:

Used in the test as an experimental animal were 6-week aged, male ratsof KBL Wistar strain that had been observed to produce no abnormalitiesin general conditions after being subjected to acclimatization for aboutone week from the purchase of the same.

(1) Stomach injury with hydrochloric acid/ethanol:

Rats weighing 193 to 228 g were kept fasting with free access to waterfor 24 hours before being used in the experiment. The rats were dividedinto groups each consisting of 8 heads in such a way that their meanbody weights were nearly uniform among the groups, treated by oraladministration of hydrochloric acid/ethanol (0.15 mole hydrochloric acidsolution in 80% ethanol) at a dose of 5 ml/kg body weight and sacrificedthrough cervical vertebrae dislocation 1 hour after administration. Thestomachs were removed and treated with formalin, and individual ulcersformed in the glandular portion of the stomach were measured in length(mm), with the measured ulcer lengths summed for each rat. The testcompound was suspended in a 0.5% aqueous solution of sodiumcarboxymethylcellulose, and the suspension was given to the test grouporally at a dose of 10 ml/kg body weight 30 min before administration ofhydrochloric acid/ethanol, whereas the vehicle (0.5% aqueous sodiumcarboxymethyl-cellulose) alone was applied to a control group. Theresults are shown in Table 4 :

                                      TABLE 4                                     __________________________________________________________________________    Test  Dose Incidence                                                                          Ulcer coefficient                                                                       Suppression                                                                         UD.sub.50 (mg/kg)                             compound                                                                            (mg/kg)                                                                            of ulcer                                                                           (mm) mean ± S.E.                                                                     %     (95% C.L.)                                    __________________________________________________________________________    Vehicle                                                                             --   8/8  47.1 ± 6.9                                                                           --                                                  (No. 1)                                                                       Vehicle                                                                             --   8/8  52.5 ± 10.1                                                                          --                                                  (No. 2)                                                                       Vehicle                                                                             --   8/8  36.5 ± 5.3                                                                           --                                                  (No. 3)                                                                       TTZ   12.5 8/8  32.2 ± 4.9                                                                           11.8.sup.c)                                               25   8/8  24.6 ± 8.8                                                                           63.3.sup.b)                                                                         22.8                                                50   5/8   2.2 ± 1.1*                                                                          96.3.sup.a)                                                                         (21.8-23.8)                                   FTZ   50   8/8  30.4 ± 7.8                                                                           35.5.sup.a)                                               75   8/8  30.2 ± 10.2                                                                          42.5.sup.b)                                                                         86.0                                                150  8/8  11.7 ± 4.7*                                                                          67.9.sup.c)                                                                         (80.6-91.7)                                   __________________________________________________________________________     Notes:                                                                        .sup.a) Suppression in Vehicle No. 1.                                         .sup.b) Suppression in Vehicle No. 2.                                         .sup.c) Suppression in Vehicle No. 3                                          *Level of significance, P < 0.01.                                        

(2) Stomach injury through water-immersion constraint stress:

Rats weighing 183 to 235 g were kept fasting with free access to waterfor 24 hours before being used in the experiment. The rats were dividedinto groups each consisting of 8 heads in such a way that their meanbody weights were nearly uniform among the groups, stress-loaded bysoaking the animals placed in a stress cage of Univ. of Tokyo type in awater tank at 23° C. up to the xiphoid and then sacrificed throughcervical vertebrae dislocation 7.5 hours later. The stomachs wereremoved and treated with formalin, and individual ulcers formed in theglandular portion of the stomach were measured in length (mm), with themeasured ulcer lengths being summed for each rat. The test compound,suspended in a 0.5% aqueous solution of sodium carboxymethylcellulose,was given to the test group orally at a dose of 10 ml/kg body weight 30min before the water-soaking constraint, whereas the vehicle alone wasapplied to a control group. The results are shown in Table 5.

                                      TABLE 5                                     __________________________________________________________________________    Test  Dose Incidence                                                                          Ulcer coefficient                                                                       Suppression                                                                         UD.sub.50 (mg/kg)                             compound                                                                            (mg/kg)                                                                            of ulcer                                                                           (mm) mean ± S.E.                                                                     %     (95% C.L.)                                    __________________________________________________________________________    Vehicle                                                                             --   8/8  31.9 ± 4.1                                                                           --                                                  (No. 1)                                                                       Vehicle                                                                             --   8/8  22.9 ± 4.4                                                                           --                                                  (No. 2)                                                                       Vehicle                                                                             --   8/8  34.7 ± 3.7                                                                           --                                                  (No. 3)                                                                       TTZ    50  8/8  19.9 ± 4.6                                                                           37.6.sup.a)                                               100  8/8   9.8 ± 2.3*                                                                          57.2.sup.b)                                                                          72.8                                               150  8/8    7.6 ± 1.4**                                                                        78.1.sup.c)                                                                         (69.1-76.7)                                   FTZ    50  8/8  28.5 ± 4.6                                                                           10.7.sup.a)                                               100  8/8  14.4 ± 3.2                                                                           37.1.sup.b)                                                                         146.9                                               150  8/8   17.9 ± 3.2**                                                                        48.4.sup.c)                                                                         (139.0-155.2)                                 __________________________________________________________________________     Notes:                                                                        .sup.a) Suppression in Vehicle No. 1.                                         .sup.b) Suppression in Vehicle No. 2.                                         .sup.c) Suppression in Vehicle No. 3                                          *Level of significance, p < 0.01.                                             **Level of significance, p < 0.01.                                       

The above results indicate that TTZ, or the compound of this invention,exhibits improved suppressory activity in the antiulcer test, ascompared with FTZ used as a control.

4. Acute toxicity test:

Rats of KBL Wistar strain (weighing about 20 g), divided into groupseach consisting of 3 heads, were treated through oral administration ofthe test compound suspended in powder gum arabic, followed byobservation for any abnormalities over a 7 day period to find the numberof dead animals. As a result, TTZ at doses up to 5,000 mg/kg did notcause any animal to die, thus leading to confirmation that the compoundof the present invention shows an extremely enhanced degree of safety incontrast with its effective doses. The results are shown in Table 6.

                  TABLE 6                                                         ______________________________________                                                         Dose                                                         Test compound    (mg/kg)  Nd/No*                                              ______________________________________                                        TTZ              1,250    0/3                                                                  2,500    0/3                                                                  5,000    0/3                                                 FTZ              1,250    0/3                                                                  2,500    0/3                                                                  5,000    0/3                                                 ______________________________________                                         Note                                                                          *Nd = No. of dead animals; No = Total No. of                             

Industrial Applicability

The novel 2-aminoethanesulfonic acid zinc complex compound of thepresent invention, in the anti-hepatitis test, can produce an improvedeffect as compared with 2-aminoethanesulfonic acid, glutathione andglycyrrhizin that were known, and also possesses an action to strengthenthe hepatic detoxification effects against a great variety of compounds,such as a potent protective effect against the lethal toxicity ofacetaldehyde, a metabolite of ethanol. Furthermore, the novel2-aminoethanesulfonic acid zinc complex compound showed markedlydistinct suppressory activity in the anti-ulcer test, while in thetoxicity test, it was also confirmed to show an increased degree ofsafety. Consequently, the present invention can provide a novelmedicinal drug that can exhibit anti-hepatitis activity, liver functionimproving activity and anti-ulcer activity in combination.

We claim:
 1. The 2-aminoethanesulfonic acid zinc complex compound asrepresented by the formula: ##STR4##
 2. A process for producing the2-aminoethanesulfonic acid zinc complex compound as represented by theformula: ##STR5## which comprises reacting a zinc compound with analkali metal 2-aminoethanesulfonate.
 3. A pharmaceutical compositioncomprised of a therapeutically effective amount of the compound of claim1 and a pharmaceutically acceptable carrier.
 4. The pharmaceuticalcomposition of claim 3 which is an anti-hepatitis agent, liver functionimproving agent and anti-ulcer agent and which contain as an activeingredient the 2-aminoethanesulfonic acid zinc complex compound asrepresented by the formula: ##STR6##
 5. A method of improving the liverfunction activity of a patient in need of such treatment which comprisesadministering to said patient a liver function improving amount of apharmaceutical composition comprised of a therapeutically effectiveamount of the compound of the formula: ##STR7## and a pharmaceuticallyacceptable carrier.
 6. A method for treating ulcers in a patient whichcomprises administering to said patient a therapeutically effectiveamount of a pharmaceutical composition comprised of a therapeuticallyeffective amount of the compound of the formula: ##STR8## and apharmaceutically acceptable carrier.